Fix the following bug, which was reported after a command line "reboot":

 WARNING: at kernel/lockdep.c:2280 lockdep_trace_alloc+0x40/0x50()
 Modules linked in:
 [<c002d910>] (unwind_backtrace+0x0/0xdc) from [<c003bba8>] (warn_slowpath+0x68/0x8c)
 [<c003bba8>] (warn_slowpath+0x68/0x8c) from [<c005ecf0>] (lockdep_trace_alloc+0x40/0x50)
 [<c005ecf0>] (lockdep_trace_alloc+0x40/0x50) from [<c0091e14>] (__kmalloc+0x58/0x110)
 [<c0091e14>] (__kmalloc+0x58/0x110) from [<c0165044>] (kvasprintf+0x38/0x58)
 [<c0165044>] (kvasprintf+0x38/0x58) from [<c015e794>] (kobject_set_name_vargs+0x14/0x54)
 [<c015e794>] (kobject_set_name_vargs+0x14/0x54) from [<c019b9ac>] (dev_set_name+0x20/0x2c)
 [<c019b9ac>] (dev_set_name+0x20/0x2c) from [<c0031804>] (davinci_watchdog_reset+0x1c/0xb0)
 [<c0031804>] (davinci_watchdog_reset+0x1c/0xb0) from [<c0029304>] (arm_machine_restart+0x24/0x50)
 [<c0029304>] (arm_machine_restart+0x24/0x50) from [<c0028d84>] (machine_restart+0x18/0x20)
 [<c0028d84>] (machine_restart+0x18/0x20) from [<c004ba80>] (sys_reboot+0xe0/0x1c4)
 [<c004ba80>] (sys_reboot+0xe0/0x1c4) from [<c0027d40>] (ret_fast_syscall+0x0/0x2c)

The issue is that dev_set_name() may no longer be called with IRQs disabled.
Trivial fix:  don't cons up a fake watchdog device, just use the real one.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>